Vitamin D Insufficiency

• Levels of serum 25(OH)D (1 ng/mL = 2.496 nmol/L)
  • Sufficient: controverisal, may be ≥30 ng/mL, optimal level is ~40 ng/mL (~100 nmol/L), some recommend levels up to 60 ng/mL
  • Insufficient: 10-29 ng/mL
  • Deficient: <10 ng/mL
  • Excess (?): >50-60 ng/mL, some evidence links potential adverse effects to high levels

• Risk factors
  • Winter at higher latitudes (November through March)
  • Breast-fed infants
  • Darker skin
  • Malabsorption
  • Obesity
  • Lifestyle-related low UVB exposure
    • Sunscreen use
    • Newborns with exclusive breastfeeding
    • >50 years old due to time spent indoors, decreased skin conversion

• Low 25(OH)D levels are associated with:
  • Respiratory infections, wheezing, asthma exacerbations
    • No association with incidence childhood asthma
  • Decreased corticosteroid responsiveness
  • Winter-related AD
  • Possible increased risk of food allergy (vitamin D sufficiency may be an important protective factor against food allergy in the first year of life)
  • Emerging data support benefit for infection

Vitamin D Supplementation

Dietary

• Dietary intakes has modest effect on level

Daily intake	Effect on serum 25(OH)D level (ng/mL)-------
Glass of vitamin D milk (100 IU)-------	+1
200 IU	+2
400 IU	+4
1000 IU	+10

Note:

• Cod liver may contain 400-1360 IU/tablespoon
• Salmon (3 oz) 447-794 IU, fortified orange juice (8 oz) 137 IU, egg (1) 41 IU, vitamin D milk (8 oz) 120 IU
• Skin can create thousands of IUs after 15-20 min of UVB exposure

Treatment

Holick

Cause of deficiency	Preventive and Maintenance Measures to Avoid Deficiency	Treatment of Deficiency
Inadequate sun exposure or supplementation Dark skin (up to 18 yo) Decreased 7-dehydrocholesterol in skin because of aging (over 50 yo)	Children 400–1000 IU vitamin D3/day (1000–2000 IU of vitamin D3/ day is safe) Maintenance dose is 400–1000 IU of vitamin D/day Sensible sun exposure Adults 800–1000 IU of vitamin D3/day 50,000 IU of vitamin D2 every 2 wk or every mo Sensible sun exposure or use of tanning bed or other UVB radiation device (e.g., portable Sperti lamp) Up to 10,000 IU of vitamin D3/day is safe for 5 mo Maintenance dose is 50,000 IU every 2 wk or every mo	Children 50,000 IU of vitamin D2 every wk for 8 wk Adults 50,000 IU of vitamin D2 every wk for 8 weeks; repeat for another 8 wk if 25-hydroxyvitamin D <30 ng/ml

Misra

• Infants and children who are vitamin D insufficient or deficient:
  • Replacement
    • 1000 IU/day of vitamin D for infants <1 month old
    • 1000-5000 IU/day for children 1-12 months old
    • >5000 IU/day for children >12 months old
    • For patients who demonstrate poor compliance, a high dose of vitamin D may be given as a single dose or repeated intermittently
  • Maintenance: 400 IU of vitamin D/day
  • Simultaneous calcium supplementation is necessary because of the risk of hypocalcemia from decreased demineralization of bone and increased remineralization as PTH levels normalize
• Blaiss: as far as dosing, I agree with the Pediatric 2008 article by Misra et al. Usually it will take up to 2-3 months in children deficient to get a therapeutic level so watch serum levels.

IOM Recommendations (2010)

References